Specifications

Using Callable System Routines
10.3 System Services
that calls the $CREPRC system service to create a subprocess to perform certain
functions for an application.
System services can be divided into functional groups. Table 10–2 lists each
group of system services and its function.
Table 10–2 Functional Groups of System Services
Services Group Function
AST Process execution can be interrupted by events (such
as I/O completion) for the execution of designated
subroutines. These software interrupts are called
asynchronous system traps (ASTs) because they occur
asynchronously to process execution. System services
are provided so that a process can control the handling
of ASTs.
‡Cluster Event Notification Cluster event notification services manage notification
requests of cluster configuration events.
Condition-Handling Condition handlers are procedures that can be
designated to receive control when a hardware or
software exception condition occurs during image
execution. Condition-handling services designate
condition handlers for special purposes.
DECdtm DECdtm services provide for complete and consistent
executions of distributed transactions. DECdtm
services coordinate distributed transactions by using
the two-phase commit protocol, and by implementing
special logging and communication techniques.
DECdtm services do the following:
• Start transactions
• End transactions
• Abort transactions
Event Flag A process can use event flags to synchronize sequences
of operations in a program. Event flag services clear,
set, and read event flags, and place a process in a wait
state pending the setting of an event flag or flags.
File Management File management services provide searching
and parsing operations of file specifications and
management of the default directory specification.
‡AXP specific
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10–5